Method and apparatus for recovery of fibers from liquids



A. M. R. KARLSTROM June 11, 1929.

METHOD AND APPARATUS FOR RECOVERY OF FIBERS FROM LIQUIDS Filed Aug. 2s, 192v qua /rm R. 11?. Kari 6 276m Patented Jam 11 1929. 1

UNITED STATES PATENT OFFICE! ADOLF MAGNUS RUPERT KARLSTR6M, OF HYLTEBRUK, SWEDEN.

METHOD AND APPARATUS FOR RECOVERY OF FIBERS FROM LIQUIDS.

- Application filed August 23, 1927, Serial No. 214,949, and in Sweden September 7, 1926.

The present invention relates to methods and apparatus for the recovery of fibers from liquids-containing fibers and has for its principal object the recovery of fibersfrom waste or back-water from cellulose, paper and wood-grinding mills.

The recovery-of .paper-pulp-fibers from the back-water has been effected, for instance, by deposition tanks or so called funnel filters, into which the back-water is introduced. In this apparatus the back-water is supplied from above and the purpose is that the fibers might sink to the bottom While clarifiefd'water runs off at the top of the tank or funnel. This method is suitable only when the fibers are heavy by some loading material. In opposite case a great portion of the fibers will rise instead of sinking down in the tank. -The reason of this factisthc air bubbles adhering to the fibers.

Also other prior methods'to recover the fibers from the back-water have not given satisfactory results. T

The present invention enables the recovery of the fibers by a method'consistin therein that the liquid containing fibers an mixed with air or gas is introduced into a Th tank sothat 'the fibers with the aid of air or gas bubbles are lifted up and collected in the upper portion of the tank, while the clarified water is discharged from the lower portion of the tank. In order to hasten the upward movement of the fibers, the liquid is sucked u into the tank whereby the air or gas bubb es get an increased power torise. In the upper portion of the tank the fibers certainly let ofi a great or air but are prevented rom sinking down by so to speak loaded fibers pressing on from. below.

In many cases the waste or' back-.water, when it leaves the work-place, is sufliciently mixed with air to enable a direct treatment of 'the liquid. In opposite case air or gas easily can be introduced.

In the manufacture of pa er sized by resin, a considerable quantity 0 resin in finelydivided state escapes with the backwater; As the air,bubbles show a gre'attendency to ad here to these resin particles the latter willaccompany the fibers and accelerate the rising movement thereof. The resin particles'are recovered with the fibers whereby a considerable saving of resin is attained.

Some embodiments of an apparatus for portion of the gas upwardly. Therlower end of the tank pro jects down into an open vat or reservoir 2 to the bottom of which a discharge conduit 3 is connectedf In'the centre of the tank there enters an inlet or supply conduit 4 for liquid-containing fibers and mixed with air or gas which conduit within the tank widens [towards the discharge end as shown at 5.

The portion 50f the conduit 4 is substantially vertical so that the liquid to be treated is supplied to the-tank in an upward current. Iii-order to prevent a sudden change of the movement direction of the particles nearest to the wall of the inlet pipe, the upper edge of the pipe may be provided with a horizontal flange or collar 51.

From the upper portion of the tank there extends a conduit 6 with a regulating valve 7 through which conduit the fiber ,mass8 I risen in the tank is sucked off by a vacuumliquid-pump (not shown in this figure). 1s pump keeps up the liquid column in the tank. The quantity of the mass drawn off from the tank and consequently the concentration thereof is regulated by the valve 7.

The arrangement according to Figure 2 differs from that one shown in Figure 1 therein that the reservoir 2 is dispensed with and the tank 1, tapering also with its lower end, 1s connected directly to the discharge conduit 3.

The embodiments .above described are shown diagrammatically while Figure 3 'shows a practical embodiment of the inven tion. In this embodiment the conduit 4 with an open end projects down into the reservoir 2- which has substantially smaller dimensions than the tank 1 which rests on a suitable frame 10. The lower end of the tube 4 can be extended by a sleeve 11 .which is displaceable along the tube. Said end of the tube 4; can be'shut oif by'means of a valve comprising a vertically movable plate or disc 12. The upper, widened portion 5, 51

- of the 'conduitl has the shape of a retarding nozzle. The liquid space of the reservoir 2 by a conduit 13 is connected with a reservoir 14 in which the airing of the liquid, entering through a conduit 15, takes place. The airing can be effected by ;compressed air or,

as iii-this case, by an injector device 16. v

' escapes.

to the injector through a conduit 17 and sucks in air through a conduit 18. Foam formed Within the reservoir 14 is also drawn in by the injector through a conduit 19. The air spaces of the'reservoirs 2 and 14: stand in connection witeach other by a conduit 20 through which foam is sucked from the reservoir 2[ The discharge conduit 3 from the tank 1 projects ,down into a reservoir 21 serving as water-trap. By elevating or lowering of the Water level in this reservoir the suction lift for the pump 22; in the conduit 6 can be regulated. Through the eonduit3the clarified water Of the valves 7 and in the'conduit 6 the former is used for the regulation of the mass drawn off while the shutting of the apparatus is efi'eeted by the valve 7 Prior to the starting of the apparatus the valves 12 and 23 are shut oif, which latter apparatus is filled with water for which purpose a particular conduit 24 may be pro.-

vided. After the apparatus thus being filled the pump 22, which keeps the Water column in the tank 1 up, is started and the valves 12 and 23 are opened. {The liquid then runs from the reservoir 14 to the reservoir 2 and through the pipe 4 up into the tank 1,- where the fibers with air adhered thereto move up to the outlet at 6 and the clarified water over the edge of the flange or collar 5 through through the pipe 3.

The liquid containing the fibers is supplied the bottom of the tank 1 is conducted out As above mentioned, instead of air another suitable gas ma be introduced into the liquid which is to be reed from the fibers;

. The carrying out of the method is not limited to apparatus of the construction above described but any other suitable arrangement may be employed therefor.

What I'claim is: ,i 1'. A method for the recovery of fibers from liquids consisting'in combination, the

introduction'of theliquid mixedwith gas intoa tank in an upwardly directed. current and the maintaining of areduced pressure within th e tank, whereby the fibers -by ad-' herin'g gas bubbles are lifted up to the surface of the liquid from which they are then separated.

2. A. method as claimed ilrclaim 1-wherein the fibers lifted :up to the surface of the valve 23 is provided in the conduit 3. The; liquid are sucked ofi from the tank.-

valves? and 7 are opened whereupon the- 3. A method for they recovery of fibers ,asaid tank by a pump so that the fibers by adhering gas bubbles are .lif tedfup to the surface of the liquid wherefrm they are sucked off from the tank by said pump.

In witness whereof I have hereunto set 'InyhaDdQ'.

ADOLF menus RUPERT K nsmen; 

